Boiler-furnace.



G. DE GRAHL.

BOILER FURNACE. APPLIOATIQN FILED K0120, 1911.

1,073,039. Patented Sept. 9, 1913.

1 2 SHEBTS SHEBT l.

Patented Sept. 9, 1913.

2 SHEETS-SHEET 2.

Fig.5.

UNITED srATr.

S PATENT OFFICE.

GUSTAV DI GBAHL, OI ZEHL'RNDORF, NEAR BERLIN, GERMANY.

roman-rename.

Specification of Letters Patent.

. .Applieationmed November 20, 1911., Serial No. 661,352.

' PatentedSept.9,191-3 To all whom it may concern Be it known that I,GUSTAV on Grmrin, a subject of the German Emperor, and residing atZehlendorf, near Berlin, Germany,

have invented a certain ncwand useful Improvement in Boiler-Furnaces, ofWhichthe following is a specification. My invention relates to methods,of auto-. matically admitting overgrateblasts. into fire-boxes, and toapparatus for carrying the same into practice.

l/Vhen overgrate blast was admitted into the fire-box heretofore, itWasfrequently diflicult for the under-grate blast to pass through thegrate, this being due, for example, to the grate having been charged toothickly or to low-grade coal. In all cases when the passage of theundergrate blast through the grate is impeded, the admission of theovergra-te blast, on the-contrary, is accelerated while being drawn in,so that the conditions are such as to favor the cooling of the fuel onthe grate and the formation of dead places, that is places where thefuel is not properlyburnt through.

A primary object of my invention is to obviate this defect. To this endI provide that the section of the passage admitting the overgrate blastis automatically reduced-both in proportion as the passage of the undergrate blast through the grate is rendered difficult during the mainblast and as the velocity of admission of the overgrate blast into thefire-box is conse uently increased. and, also according to the initialvelocity of the overgrate blast.

By restricting the passage for the overgrate blast the conditions arerenderedfavorable for drawing the undergrateblast through the grate.Consequently, the object of my method is automatically to restrict theadmission of the overgrate blast or; to cut it off completely assoonasit detrimentally 'alfects the process of combustion and thus favorablyto influence the passage of the undergrate blast through the grate.

The apparatus substantially consists in the conduit which not onlyadmits the supplementary air or overgrate blast and opens into thefire-box, but is alsoprovided with a valve opening inward being soconstructed, for example, by the addition of a projection, rib or thelike, that the valve constricts the free section of the passage for thesupplementary air as it opens beyond a certain amount and approaches thelimit of its travel.

In order to vary the restriction of the passage to suit the coal burnedat any time and, particularly, to prevent the passage for the overgrateblast being restricted too much when the coal develops a great deal-ofsmoke, I, provide an adjustable stop for the valve. The valve may, forexample, be so adjusted that when using) steam coal the passage for theovergrate last is almost completely closed owing to the velocity atwhich said blast enters, whereas for coal developing much soot it isonly slightly restricted or not at all. One for m of apparatus accordingtomy inventlon is represented by way of example in the accompanyingdrawings, wherein Figure 1 is a front elevation of a fire-door framehaving an inwardly opening fire-door, Fig. 2 a front elevation, partlyin section, enlarged, showing a portion of the fire-door frame, and Fig.3 is a horizontalsection on the bent line AB in Fig. 2. Referring to thedrawing, 1 designates the door frame provided with two lateralairconduits 2, 3. I Each of these has an enlargement 4, 5 respectively,which is separated by a projection or rib 6, 7 from the upper portion ofthe air-conduit. In each of said lateral air-conduits there is an airvalve 8, 9 mounted on a pivot 10, 11, respectively. On the wall of eachlateral air-conduit is fixed a segment 12, 13, connected by arms 14, 15with a sleeve 16, 17. Each of the latter extends through the wall of.the lateral air-conduits 2, 3 above the valves and serves for thereception of a revoluble pivot 18 which carries on the end projectininto the lateral air-conduit a lever 19 actlngas a. stop for the valves,and on the other end a lever 20. Each lever 20 carries a handle 21having a recess 22 (Fig. 3). Thespring 23 in each recess 22 acts againstthehead 24 of the pointed pin 25. The pins are displaceably mounted inthe handles 21 and are provided with nuts 26.

The segments 12, 13 each possess a series of notches or holes 27, 28inwhich the pointedends of the heads 24 can rest. The levers 19, 19- areprovided with springs 29, 30 which serve as resilient stops for thevalves 8, 9. The position of each lever 20 with regard to the valves 8,9 is such that as soon as the head 24 engages in the lower- 'a minimumamount,

most hole 27 or 2%,thc lever 19 formingthe stop for the valve allows thevalve to open just sufficient to cool the furnace front. Atter steam hasbeen shut ofi' from the engine and after the main blast has ceased, theresilient stops for the valves 8, 9 are adjusted according astheauxiliary blast is set more oi iless in action,

' the arrangement being such that even when the valves. have openedawcomparatively small amount there is a comparatively large opening forthe overgrate blast passing through the air-conduits. If, after theauxiliary blast is shut off the main blast is started, in case thepassage of the undergrate blast through the grate is rendered difficultin consequence, for example, of the grate being too heavily charged andthe velocity of the overgrate blast passing.

I to appear on the grate, their appearance being always a proof thatinsufficient undergrate air is passing through the grate into the spaceabove the grate. In this case main, in consequence of the great velocity0? the over-grate blast passing through the air-conduits 2, 3, theair-valves 8, 9 automatically adjust themselves in such manner that theadmission of overgrate blast is impeded and consequently dergrate blastthrough the grate favored. Should the one side of the grate be morechoked or stopped up than the other, so that overgrate blast is drawn'into an increased extent at this choked up side and combustionconsequently takes place more slowly at said side, the automaticregulating action described above will take place 'only in the case ofthat valve which is situated at said side of the furnace.

For short flaming coal which tends to develop smoke only slightly, it ispreferable to set the levers 19 provided with the stops for the valvesin such a manner that the valves occupy the upper position indicated inFigs 2 as soon as they bear against'the resilient stops. In this casethe passage for the overgrate blastis materially restricted. Inproportion as the coal tends to develop soot such a position should begiven to the lever 19 that the restriction is less. The

the passage of un-.

above described device is ithus such? that,

each kind of coal, it enables the passage ror the oye'rgrate blast to beadjusted automatically.

I clai'm V after the levers 19 have been suitably set for 1. "Apparatusfor automatically control-=- ling the fire box of the furnace,comprising in the admission of overgrate blast into combination, asuction copduit for the overgrate blast open at one nd tot-he'outeratniosphere and at the otherendto the'fii'e box rib extending throughthe suction and being said conduit being provided with an internalimmovable 1n the same, thus narrowing the said conduit, and a. valve insaid conduit opening toward the fire boxadapted to approach said rib andrestrict the'passage for the overgrate for said valve.

2. Apparatus for automatically com r blast, and an adjustable stop lingthe admission of over-grate blast into I the fire box of the furnace,comprising in combination, a suction conduit for'the overgrate blastopen atone end to the outer atmosphere and at the other end to the firebox said conduit being provided with an internal rib extending throughthe suction conduit and being immovable in the same, thus narrowing thesaid conduit, and a valve in said conduit opening toward the fireq boxadapted to approach said r ib and restrict the passage for theover-grate blast, and an adjustable resilient stop for said valve. N

8. Apparatus for automaticallyi'controlling the admission of overgrateblast into the fire bOXJPi a furnace, comprising incombination,,a'-'suction conduit for the overgrate blast open at one end'to 'theouter atmosphere and vat the other end to the fire box, saidconduit being provided with an inwardly projecting rib, a chamberbetweensaid rib and the atmosphere, a pivoted valve mounted in said conduit onthe atmosphere side of said chamber, said valve being adapted to closesaid conduit when no air is passing therethrough andto swing through .7

said chamber toward said rib under the influence of an increasingsuction whereby said condult 1s first opened and then restricted as thevalve moves toward said rib, and an adjustable stop for limiting themovement of said .valve toward said rib.

In testimony whereof, I atfix signature.

in the presence of two witnessesia v U AY? be .GRVAHL: 1

Witnesses:

HENRY HASPER, WOLDEMAR HAUPT.

